What do you mean? I only need a jb not an unlock, but is it safe to go on 4.1 since i only need the jb not unlock, and ofcourse i have no shsh blobs for 4.0.1 or 4.0.2 saved?

There is currently no jailbreak for 4.0.2 and 4.1, but the baseband for the 4.0.2 is unlockable and the 4.1 is not.
So for future for resale I would unlock and sell at a higher price, but if that is not an issue with you then I would just upgrade and wait for the jailbreak to come.

The only real gain you get from 4.1 is HDR photos and GameCenter, and they both aren't worth the upgrade in my honest opinion. The HDR photos look over exposed, and the GameCenter is pointless. So I would keep it on 4.0.2, just to be on the safe side regarding the baseband. Though if you are sure you won't need the unlock ever, then there's no harm upgrading to 4.1. Hope this helps!